Integrated, unijunction transistor oscillators

The unijunction transistor (UJT) is being considered as the active element in an integrated harmonic oscillator realization. Necessary and sufficient conditions for oscillation in the harmonic mode have been determined. The dependence of the frequency constancy factor,\frac{1 d\omega_{o}}{\omega_{o} dT}, on device temperature and bias-conditions is derived. These results depend on an a.c. perturbation analysis of the UJT. The analysis brings out in detail the known behavior of the UJT input port as a -R, L network at low frequcndcs. The input port is also shown to function as a +R, C network at high frequencies. A natural resonance in the diffusion process at medium frequencies is pointed out. An intrinsic UJT oscillator is proposed, based upon this resonance. Experimental work with commercially available UJT structures substantiates analytical results. Experimental studies of prototype oscillator circuits are used to design an integrated oscillator realization which is optimized with regard to temperature stability and waveform distortion.